Monopole structure



FIG. 1 is a front perspective view;

FIG. 2 is a back perspective view;

FIG. 3 is a front view;

FIG. 4 is a back view;

FIG. 5 is a side view;

FIG. 6 is an opposite side view;

FIG. 7 is a bottom view; and,

FIG. 8 is a top view.

The design is shown broken away in the middle to indicate that a specific length of monopole structure forms no part of the claimed design. 

The ornamental design for monopole structure, as shown and described. 